Flange false twist textured nylon

ABSTRACT

A novel monofilament nylon yarn suitable for use in knit constructions, particularly women&#39;&#39;s hosiery, characterized by boardability, twist liveliness and knitability values is disclosed. A combination false twist, topcoating finish application process is disclosed as exemplary of methods to produce the yarn. This process may be a simultaneous or sequential drawing, false twisting operation utilizing a twist insertion flange.

United States Patent Steinmiller [54] FLANGE FALSE TWIST TEXTURED NYLON [72] Inventor: William George Steinmiller, Charlotte,

[73] Assignee: Fiber Industries, Inc.

[22] Filed: Oct. 27, 1970 [21] Appl.No.: 84,387

[52] U.S.Cl. ..57/140 C,57/153,57/l57 TS, 7 57/164 [51] Int. Cl. ..D02g 1/02, D02g 3/36 [58] Field ofSearch ..57/l57 TS, 164, 34 HS, 140 R, 57/140 C, 153

[56] References Cited UNITED STATES PATENTS 2,946,180 7/1960 Tissot et al ..57/34 HS 51 Mar. 28, 1972 3,094,834 6/1963 Deeley et a1. ..57/34 HS 3,365,874 1/1968 Chidgey et a1 ..57/157 TS 3,425,208 2/1969 Shipee et a1 ..57/157 TS 3,434,277 3/1969 Maeda et al.... ...57/157 TS 3,462,938 8/1969 Mehta ...57/157 TS 3,535,866 10/1970 Tsuruta et al. ..57/34 HS Primary Examiner-John Petrakes AttorneyStephen D. Murphy and Louis Gubinsky [5 7 ABSTRACT A novel monofilament nylon yarn suitable for use in knit constructions, particularly women's hosiery, characterized by boardability, twist liveliness and knitability values is disclosed. A combination false twist, topcoating finish application process is disclosed as exemplary of methods to produce the yarn. This process may be a simultaneous or sequential drawing, false twisting operation utilizing a twist insertion flange.

14 Claims, 2 Drawing Figures Patented March 28, 1972 2 Sheets-Sheet l mwwz3w 3 Z :5 02 com on 02 0% com S m 00m o? o? I 1 I Q. l I l x 1 a QN 9 Q Q on o w BOARDABILITY FACTOR INVENTOR WILLIAM G STEINMILLER FIG.

ATTOR NE Y Patenfecl March 28,1972 3,651,633

2 Sheets-Sheet 2 F I 2 INVENTOR WILLIAM G. STEINMILLER BY L ATTRNEY FLANGE FALSE TWIST TEXTURED NYLON BACKGROUND OF THE INVENTION The present invention relates to a special false-twisted nylon monofilament yarn and a process for its production.

Twist-lively monofilament nylon yarn is widely used in the production of hosiery, particularly womens stretch hose. A number of yarn properties inter-act to afi'ect the ultimate suitability of a particular yarn for this end use. For example, a minimal torque value is required for a yarn to be suitable in a plain knit hose construction, especially where stretch" hose (a single hose construction which stretches" to conform to all or a selected range of normal foot sizes) is to be the ultimate product. Although torque is a valuable comparative characteristic between yarns of the same denier, a more exact indicator of potential yarn contraction as translated into product contraction or post-autoclave length in a knit hosiery product, particularly to evaluate yarns of different deniers, is a twist livellness value obtained as the product of torque and denier. This latter function of twist-liveliness, as discussed in greater detail in the detailed description of the invention hereinafter, is used as one parameter to gauge the processability, and hence product advantages of the novel yarn of the invention as compared with the yarns of the prior art.

Apart from the consideration of torque, two other characteristics of the yarn, namely post-autoclave length and equivalent steam set temperature (ESST) markedly affect the extent of board conformation of the knit product, and hence the quality of the finished and boarded hose. The critical feature of the boarding process involved with these two yarn propertiesis the ability of the contracted fabric to fit snugly around the narrow ankle area of the form and conform to the new shape with adequate definition during the steam setting process. Post-autoclave length and ESST are appropriately correlated into an expression of monofilament yarn boarda bility by a boardability factor as developed in the detailed description of the invention hereinafter. The boardability factor of the yarn operates as a second parameter to establish the improved properties of the novel yarn of the invention as compared with the yarns of the prior art. A graphical representation is utilized, plotting boardability and twist-liveliness yarn values as abscissa and ordinate functions respectively, to pinpoint the yarn of the invention with respect to both of the defining parameters, and as compared with the yarns of the prior art.

Additionally, the yarn must be pressable on conventional hosiery knitting machines, i.e., circular knitting machines, with a minimum of yarn breaks and the like. Yarn processability is especially significant as the yarn is unwound from the package to be fed into the knitting operation, that is, prior to the point where the knitting converter has a first opportunity to apply a knitting improvement finish to the yarn. Without adequate yarn antistatic and lubricant protection on the pirn, excessive and/or uneven yam tensions develop as the yarn is unwound from the pirn and guided into the knitting machine.

Various processes have been used to impart the abovedescribed properties to nylon monofilament yarn and articles made therefrom, such as hosiery, pantyhose and other items of inner and outer apparel. One such technique involves false twist texturing wherein the yarn is fed to a rotating false twist spindle which positively engages it, putting in Z or S twist upstream of the spindle and taking out precisely the same amount of opposite twist downstream. The yarn, while twisted, is passed through a setting zone so that its bias to remain twisted is locked therein. The yarn is collected, a processing finish is applied to the yarn as it is guided into the conversion machine to be made up into fabric and, upon release, the fabric shortens due to contraction of the yarn which can be compared to an extended coil spring. Stretching force serves again to stretch the fabric to any extent up to the fully uncoiled length of the component yarns.

While this system largely overcomes the disadvantages of earlier systems, when running at high speeds on monofilament yams it is found that the products so produced as well as the process require improvement for commercial acceptance.

Therefore, it is an object of the present invention to provide a novel false twist textured nylon monofilament yarn of superior properties for use in hosiery constructions.

It is another object of the invention to provide a monofilament yarn, particularly comprising poly(hexamethylene adipamide), characterized by disclosed twist-liveliness and boardability values coupled with superior knitting pressability.

It is still another object of the invention to provide knit structures, especially hosiery, constructed of the novel yam.

It is a further object of the invention to provide an improved friction false twist process to produce the novel yarn of the invention.

Other objects of the invention will appear obvious to those skilled in the art from the detailed description of the invention hereinafter.

SUMMARY OF THE INVENTION It has now been found that nylon monofilament yarn characterized by a boardability factor below 2.0, preferably between 1.0 and 2.0, more preferably about 1.0 to 1.5, a twistliveliness value below 600, preferably between about 600 and 450, more preferably between about 600 and 500, and having a coating of a finish consisting essentially of 1) major amount of a synthetic fiber lubricant selected from the class consisting of esters formed from C to C chain acids esterified with C to C chain alcohols and mineral oil of defined viscosity; (2) a minor amount of a nonionic alkoxylated emulsifier and (3) a minor amount of a C to C straight chain fatty acid alkanolamide antistatic agent, uniformly applied thereon in an amount of about 0.5 to 2.0 percent based on weight of the yarn, can be knit into hosiery constructions, particularly womens stretch hose constructions, having improved boardability, shape definition, aesthetic appearance and the like properties.

It has also been found that the aforementioned yarn may be produced by a friction false twisting process, preferably a simultaneous drawing, false twisting process utilizing a rotating flange, wherein the yarn is heated in a heating zone maintained at about 220 C., preferably l70l90 C., said heating zone being about 2 to 30 inches, preferably 2 to 10 inches, in length along the yarn path, while travelling between about 1,000 to 5,000, preferably 1,500 to 2,500 feet per minute, allowed to cool in ambient air for about 5 to 50 milliseconds after leaving said heating means; then friction false twisted under conditions to impart about 20 to 40 turns per inch of false twist in said yarn, said twist running back to said heating zone; applying the above-described finish application to the yarn and finally taking up said yarn with a ring and traveller mechanism while inserting a real producer twist, i.e., about is to I turn per inch, into said yarn by means of said ring and traveller, in the opposite direction of said false twist.

In preferred embodiments of the invention, the feed yarn is essentially undrawn and is simultaneously drawn about 3.5 to 5 times during the false twist insertion operation, the lubricant is a straight chain fatty acid ester esterified with a straight chain alkanol, the emulsifier is a C to C straight chain alcohol ethoxylated with 2 to 12 mols ethylene oxide per mol alcohol and anti-stat is a di-alkanolamide of naturally occurring cocoa fatty acids.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a plot of Boardability vs. Twist Liveliness showing the area in which the novel products fall in contrast with prior art products; and

FIG. 2 is a schematic perspective view of an apparatus for practicing the present invention.

DETAILED DESCRIPTION OF THE INVENTION In knitting hosiery from twist-lively or torque stretch yarn, the hose contract spontaneously when released from knitting tensions. The contraction for monofilament hose is typically 50 percent lengthwise, that is along the wales, and 25 percent widthwise. A further small contraction, about one-tenth of the original. occurs during a finishing steam treatment (100 C.) when the full torque potential of the yarn is released. The contracted hose, after dyeing, are boarded, i.e., stretched over a forming board, and set to their finished form by a second, higher temperature (1 18 C.) steaming.

Fabric contraction reflects a structural relaxation to a new stitch conformation, where the original flat loops produced in knitting have been turned out of the knitting plane and tilted by the fiber torque. Stitch loops in adjacent courses, which are knit from yarns of opposite twist to maintain an overall torque balance in the hose, distort in opposing directions, tilting left or right depending upon whether the yarn has S or Z torque. The interaction between these opposing distortions causing the courses to ride up over one another as the fabric structure relaxes, giving the characteristically large walewise or lengthwise contraction. The lesser contraction around the courses, the widthwise hose contraction, sums the turning distortion in individual loops.

In order to evaluate the boarding performance and final hosiery characteristics of the novel yarn of the invention and the yarns of the prior art, hose are produced in accordance with the following construction to produce a finished size 9% medium hose.

The Reading two feed Mark III circular knitting machine, manufactured by the Reading Machine Company of Reading, Pa. knits in a plain jersey single knit construction 24 courses per chain link and is set to:

patched heel "measured by Stretchette machine manufactured by Corbett Associates of Concord, North Carolina A tolerance of :95 inch is allowed on each cross section value. Welt and heel yarns are conventional spindle false twist textured 40/ l 3 continuous filament nylon 6,6 yarn. All other yarn used is constructing the hose is the yarn of the invention or prior art yarn as indicated hereinbelow.

In the knitting operation, the yarn is unwound from the package pirn of yarn and fed through a series of guides into the individual needles. As each pirn revolution of monofilament yarn leaves the pirn, it necessarily rubs against adjacent wound yarn in friction contact therewith. Tension on the yarn fluctuates and increases in accordance with friction contact compounded by static attraction. Tension differences along a single monofilament end, exaggerated by end to end variance, results in poor knitting efficiency and causes a high number of breaks between the pirn and needle. Because one of the major contributing factors lowering knitting efficiency is tension developed as the yarn leaves the pirn, the knitting converter is not in a position to alleviatethe problem.

The novel topcoated yarn of the invention, in addition to its boardability and twist-liveliness characteristics, does not present any processing problems to the knitter. In particular, yarn tension fluctuations, as well as undesired high yarn tensions, are effectively eliminated by the yarn of the invention and the integrated flange false twist-topcoating process by which it is produced.

The yarn of the invention, in addition to its defined boardability and twist-liveliness values, contains a topcoating (that is, a coating which is additional to any conventional spin finishes which could be applied to facilitate drawing and producer texturing) containing three essential ingredients uniformly applied thereon. The topcoating is applied during the producer texturing operation in an amount to provide about 0.5 to 2.0 percent, preferably 0.75 to 1.25 percent and most preferably about 1.0 percent, based on yarn weight, of the finish on the yarn.

The topcoating finish formulation consists essentially of a major amount of a synthetic fiber lubricant to lower yarn to metal and yarn to yarn friction and minor amounts of an emulsifier and antistatic agent, all as more particularly described hereinafter. All percentage concentrations are by weight unless indicated otherwise.

The lubricant, which is 40 to 90 percent and preferably 60 to percent of the finish formulation, is either mineral oil having a viscosity of about 8 to 25 centistokes at 25 C. or an ester of a C to C chain carboxylic acid with a C to C, alkyl alcohol or mixtures thereof. More particularly, when an ester is employed, the acyl portion thereof can be provided by natural, i.e., derived from animal, fish, vegetable or mineral oils, and/or synthetic branched or straight chain alkyl acids. Mixtures of acids are also contemplated wherein the average carbon chain length is within the defined range. Although the acid may contain some unsaturation i.e., an acrylic series acid, and the alcohol may be polyhydric in nature, preferably straight chain fatty acids and straight chain monohydric aliphatic alcohols are employed to produce the synthetic ester. As specific examples of the lubricant used in the topcoating finish formulation, there may be mentioned propyl laurate, hexyl palmitate, butyl stearate, butyl laurate, propyl tridecoate, butyl myristate, pentyl palmitate, hexyl pentadecanoate, propyl margarate, hexadecyl stearate, refined mineral oil having a viscosity of 20 centistokes at 25 C. and the like.

The emulsifier component of the finish provides 5 to 35 percent, preferably lO to 30 percent of the finish formulation and is selected from the class of nonionic alkoxylated emulsifiers. It is generally the condensate of ethylene oxide with an organic compound containing an active hydrogen atom. The condensate contains no more than about 12, for example 2 to 12, mols of condensed ethylene oxide per mol of organic compound. Suitable organic compounds are C to C preferably C to C fatty acids and fatty alcohols, alkyl phenols, amides of ethanol amines and fatty acids of 15 to 20 carbon atoms, fatty acid esters of polyols andthe like. As specific examples of the emulsifier, there may be mentioned the condensate of 6 mols of ethylene oxide with lauryl alcohol, ethoxylated nonyl phenol (8 mols ethylene oxide/mol phenol), the condensate of 3 mols ethylene oxide with palmitic acid, the condensate of 3 mols ethylene oxide with tridecyl alcohol, and the like. Also a mixture of alcohols having an average chain length, for Example I of 12 carbon atoms can be employed.

The third essential ingredient of the finish formulation forms 5 to 30 percent, preferably 10 to 15 percent of the finish and is a monoor dilower alkanol amide of a C to C straight or branched chain fatty carboxylic acid. The fatty acid may be natural or synthetic and preferably is not branched. Particularly with naturally occurring acids, a mixture of acids may be employed wherein the average acid chain length is within the defined range. For example, the diethanolamide of a cocoa fatty acid cut having an average fatty acid chain length of about 12 to l4 carbon atoms may be employed. The alkanolamide will contain one to four, preferably one to two, carbon atoms in each chain. As additional examples of the antistatic agent, there may be mentioned the amide of diethanolamine and palmitic acid, the amide of monomethanolamine and decanoic acid, the amide of methanolethanolamine and lauric acid, the diethanolamide of pelargonic acid and the like.

After the knitting operation, the knit hose contracts substantially in the lengthwise direction, however, a smaller degree of contraction occurs in the widthwise direction.

A second, small contraction occurs during a finishing steam treatment at about 100 C. The contracted hose, after dyeing, are stretched over a forming board and set to their finished form by a second, higher temperature (1 18 C.) steaming.

Certain definable properties of the yarn markedly affect the boarding performance, and hence final characteristics of the knit product. More particularly, the equivalent steam set temperature of the precursor yarn (with reference to nylon 6,6 and the like yarns which are relatively moisture insensitive as compared with nylon 6 and the like yarn equivalent heat set temperatures or EHST, which directly correlates to ESST, is used with the moisture sensitive yarns) and post-autoclave length of the knit hose can be combined in an empirical relationship to describe the boardability of the precursor yarn.

widthwise contraction is important, indeed a critical boarding feature, because the fabric must fit snugly around the narrow ankle area of the form in order to be properly set into the new configuration. Because monofilament yarn torque converts inefficiently with widthwise hose contraction, it is conventional to design the fabric so that its pre-boarding length is short enough to require stretching to the final boarded length, thereby generating tension which pulls the ankle region of the fabric into the board. However, torque alone does not translate into a well-defined set in practice. The hose must be heat set to a large degree during the final steaming operation on the board in order to retain the boarded configuration and shrink sufficiently in the widthwise direction around the narrow ankle areas of the form. Thus, the degree to which the yarn is still capable of being set during the final boarding treatment, markedly affects the boardability performance of the hose (hence yarn) and the quality of the finished product.

ESST (and EHST) values of the yarn describe the capability of the yarn to be heat set while simultaneously shrinking during the boarding operation, with lower ESST values correlating with a lower set prior to boarding; therefore, a greater ability to conform to the new shape. Obviously, yarn of lower ESST value is preferred for stretch hose constructions. ESST is defined by the equation ESST M0 S/K where S is the percent shrinkage of the yarn measured in steam at 140 C. and K is a proportionality constant for the shrinkage-temperature relation, which for nylon 66 is about 0.1 percentl C. and for nylon 6 is about 0.07 percent/ C. S is measured by draping 30 centimeter samples of processed yarn (preconditioned in 50 C. water for 30 minutes and air dried), free of restraint, across wire racks followed by 6 minutes of prevacuum to about 12 p.s.i.g., steaming for 6 minutes at 140 C. with saturated steam (37.72 p.s.i.g.), after which the steam is bled off under vacuum and the yarn cooled. (For nylon 6 shrinkage is determined as above with the exception of the use of hot air at 190 C. in place of the steam treatment.) Initial and final lengths of the yarn are measured under 0.06 g./denier tension at 70 C. and 65 percent relative humidity. Before measurement, each sample is conditioned in water at 50 C. for 30 minutes and air dried. The shrinkage of the novel yarns is quite high, i.e., usually more than 8 percent and sometimes 10 percent, compared with less than 4 percent conventionally false twist textured yarns. This corresponds to a ESST below 75 C. and generally below 60 C., for example 47 C. to 55 C., compared to over 100 C. for conventionally false twist textured yarns.

On the lower end of the scale, it has been determined that ESST should be at least about 40 C. to prevent unacceptable torque decay during hot, humid storage conditions.

The lower the ESST value, the less the yarn has been heat set. The less severe is the set of the yarn, the easier it is for the indicates ability in the hose to shrink and conform to the new shape, particularly about the ankle, and retain the new shape following removal from the board. The difference between the boarding temperature and ESST is the denominator in the equation defining the overall boarding performance of the yarn, according to the equation:

2 X post-autoclave length Boardabgaity factor---------- 18 C. ESSTO 0.

As apparent from the above Boardability Factor, the second value to be considered in determining boarding performance is the post-autoclave length of a standard hose, the 9% medium described above inthe present instance. Of course, other standard hose sizes may be used to determine post-autoclave length values with appropriate recalculation of boardability factor values.

The main yarn factor contributing to post-autoclave length is the torque of the yarn. Hose released from the knitting machine contracts spontaneously. A final, lesser, but more rapid contraction occurs during the first steam finishing treatment. The summation of the two contractions is indicative of the total torque of the yarn. Post-autoclave length is measured after the first steam finishing treatment between the bottom of the welt and the point of the heel from which the knitting needle reciprocates in knitting the half courses for the heel along the wales with the hose hanging by the welt under 5 grams tension. The post-autoclave length determines to what degree the hose will be stretched on the board. The lower the post-autoclave length, the better the boarding performance of the hose and hence yarn. For example, using the hosiery construction described above and a typical board used for 9% size nylon stretch hose, post-autoclave lengths below about 44 cm. produce good quality hose.

The relationship between length and boarding performance has been described hereinbefore. Hose requiring a greater degree of stretch over the board will conform more exactly to the shape of the board.

It becomes apparent that post-autoclave length and ESST, in the proper relationship, define the boarding performance of the hose, and hence the yarn. For proper weight to be given the post-autoclave length value, it is multiplied by a factor of 2 in the numerator of the boardability factor. Because post-autoclave length and ESST are both limited as to the lowest possible values, with maximum values determined by the boarding temperature and board length, the lower the boardability factor of the yarn, the better the performance of the hose.

Other factors in addition to torque affect post-autoclave length to a certain degree. For example, there may be mentioned fabric density and the various surface applications such as knitting oils which are applied to the yarn. As long as the tested hose are constructed and processed substantially identically, the measured post-autoclave lengths will be comparable on a relative basis. To derive the post-autoclave'lengths utilized herein, the standard hose leg was knit, allowed to contract under tensionless, ambient conditions for 5 days and then is steam treated at C. for 20 to 45 minutes. Boarding is at 118 C. in steam for 45 seconds in an autoclave under 25.9 pounds per square inch absolute.

Minor variation in post-autoclave length and ESST determinations do not appreciably affect the boardability factor numerical range. The important consideration is the ESST value coupled with the approximate post-autoclave length value, and the boardability factor equation takes into consideration the relative weight and exactitudes of the post-autoclave length and ESST functions.

The second parameter used to characterize the novel yarn of the invention is the twist-liveliness of the yarn. Twist liveliness is yarn torque normalized for denier by the expression:

Twist-liveliness torque X denier The importance of torque during the knitting operation and boarding has been discussed hereinbefore.

Torque is measured by a skein test as follows:

A 70 warp X 1% meter skein is wound on a denier reel. The skein is mounted on a prepared framework and tensioned with a 54.40 gm. load. The tensioned skein is held in two clamps which can be moved together by sliding along a rod. One side of the skein is cut away, leaving 7.0 ends about 19% inches long. A symmetrical cross-shaped tension weight (54.50 gms.; each of the arms is 4% inches X k inch X /4 inch aluminum, the 1% inch dimension being in the plane of the cross) is hung by a hook to the middle of the yarn bundle and the clamps are brought together, lowering the cross to 1 inch below the surface of water in a beaker.

The skein, driven by the fiber torque, twists around itself causing the cross to rotate in the water. One complete revolution is allowed for the system to accelerate to a dynamic equilibrium then the time period for the next five revolutions is recorded on a stop-watch to be quoted as the estimate of fiber torque.

Standard lag-time in a controlled environment and standard bobbin stripping procedure are followed to ensure consistent results. Obviously, as true torque increases, the numerical value of twist liveliness decreases. The novel yarn of the invention in denier is generally characterized by a torque of between about 40 and 30, preferably about 33 to 40. These values calculate to a twist liveliness range of about 450 to 600, preferably about 500 to 600. These twist liveliness values are desirable for monofilament yarns of any denier, for example, a denier yarn should have a torque below about 30 to be within the inventive concept. The twist liveliness value remains constant although torque and denier of the monofilament yarn may vary.

in accordance with the above discussion, the Boardability Factor of the novel yarn of the invention should generally be below about 2.0, preferably less than about 1.5 and most preferably about 1.0 to 1.5 with twist liveliness ranges as above disclosed.

In FIG. 1 of the Drawing, yarn twist liveliness is plotted against yarn boardability factor. The novel yarn of the invention has a boardability factor below the 2.0 and a twist liveliness below about 600. Preferably the yarn is characterized by falling within the rectangle formed by the points VXYZ (Boardability Factor of about 1.0 to 2.0 and twist liveliness of about 450 to 600); more preferably within the rectangle VWAZ (Boardability Factor of about 1.0 to 1.5 and twist liveliness of about 450 to 600), and most preferably within the rectangle UVWT (Boardability Factor of about 1.0 to 1.5 and twist liveliness of about 500 to 600).

Throwster textured yarn conventionally is characterized by the properties within the bounds of rectangle Q. The prior art produced textured nylon monofilament yarns are characterized by rectangle R.

The throwster yarn, although having adequate torque for plain knit hosiery, exhibits inferior widthwise contraction and definition around the narrow ankle area during boarding. The prior art producer textured yam does not have sufficient twist liveliness to be useable in plain knit hose constructions. Of course, the yarn of the invention is also excellent for unboarded constructions.

Turning now more specifically to the drawing, in FIG. 2 there is shown a yarn package such as a biscuit or a cheese 12 from which yarn 14 is pulled by feed roll 16, the yarn passing over guide 18 and tension bars 20, 22, then over traverse guide 24, then about the cot roll 26 which is driven by contact with the feed roll 16. The yarn passes one or more turns about snubbing pin 28 provided with an electrical element 30 to heating, after which the yarn passes toward a drawing mechanism comprising a draw roll 32 operating in conjunction with a separator roll 34, the yarn making several wraps around both to prevent slippage and then passing through trough 50 where the topcoating finish is applied by application roll 51 and to the balloon guide 36 of a ring and traveller takeup 38 by means of which it is collected on a pirn 40.

The draw roll is provided with a flange 42 which the yarn contacts transversely in its path to the roll surface. The flange 42 is provided with a relatively high friction surface, e.g., neoprene, to minimize yarn slippage thereover, the yarn being caused to twist by contact with the flange. The number of turns of twist inserted is theoretically a function of the relative diameters of the flange and the yarn although there will be some slippage whose amount depends on variables such as the type of spinning finish used.

The rotation of the flange sometimes causes the yarn to be flicked around the periphery and break out. To prevent this it has been proven beneficial to position a guide 44 in such a position relative to the flange as to maintain a more positive contact between the yarn and flange and to minimize, if not prevent, such flicking of the yarn. Surprisingly, the guide does not arrest the twist in the yarn inserted by flange 42 and therefore does not prevent the twist from travelling back to heated draw pin 28.

The invention is especially directed to a nylon monofilament yarn such as a 15 to 25 denier monofilament, although the filament may be as low as 10 denier or even 5 or as high as 50 or or more. Heterofilament yarns in which the nylon portion is one continuous segment of the yarns are also contemplated. The nylon is preferably nylon 66 i.e., polyhexamethylene adipamide, but it may be nylon 6, l0 and the like, as well as polymers of caprolactam, amine-undecanoic acid, butyrolactam, the condensate of bis[para amino cyclohexyl] methane with dodecanedioic acid, and the like, as well as copolymers thereof and aromatic polyamides such a polyhexamethylene terephthalamide. Of course, the ESST or EHST testing procedure will be appropriately modified according to the yarn polymer properties, as is apparent to those skilled in the art.

While described hereinabove as coming from a package, if desired, the yarn may be coming directly from an extruder, never having previously been collected. Possibly, it is extruded continuously with polymerization so that monomeric hexamethylene diammonium adipate goes in at one end and a drawn and textured nylon 66 monofil is collected at the other.

After leaving pin 28, the yarn cools slightly in ambient air for about 5-50, preferably 20-50 milliseconds. If desired, positive cooling means maybe employed to effect further reduction in the temperature of the yarn during the false twisting operation.

Pin temperature is between about to 220 C., preferably l70l90 C. with a pin diameter and number of yarn wraps so that the yarn path through the heating zone is about 2 to 30 inches, preferably 2 to 10 inches when the yarn speed is about 1,000 to 5,000, preferably 1,500 to 2,500, feet per minute. The desired degree of set is obtained under these conditions.

As discussed above, when setting is too extensive, the yarn does not conform as well to the new set during boarding.

These processing conditions are not suggested by the prior art such as Deely et al., US. Pat. No. 3,094,834, being directed to the production of multifilament crimped yarn. The monofilament yarn does not develop crimp, but instead becomes torque lively from the false twisting operation.

The rotation of the flange should impart at least about 15 and preferably at least 20 to 40 turns per inch of real twist in the yarn between the flange and the snubbing pin. This can be measured visually by observing the change in angle of surface striation with respect to the longitudinal axis of the yarn and calculating the twist inserted therefrom. A yarn sample snatched from the twist zone is viewed under the scanning electron microscope when in the twisted configuration between the drawing pin and the flange.

While the process has been described as producing a pirn of product, the product may be collected on a horizontally rotating shaft, as a biscuit or cheese similar to 12 All takeups have some upper limit of speed and the running yarn, where simultaneously drawn, has an optimum draw ratio to produce desirable properties and a stable process. Assuming the speed is 100 meters per minute and the draw ration is 5:1, the maximum feed speed is only 200 meters per minute. If

the feed is a filament extruder, this will necessitate running the extruder far below its capacity. It is a feature of the present invention that with any given system the optimum draw ratio is lower than otherwise because of the percentage of draw effected due to the twisting action, so that for the same takeup speed a higher extrusion speed may be used, thus operating closer to the capacity of the extrusion equipment and of the polymerization equipment if all is in series. A draw ratio of about 3.5 to 5, especially about 4.0 to 4.5 and particularly about 4.2, is preferred.

The invention will now be further described in conjunction with the following illustrative examples.

EXAMPLE 1 Using an apparatus as shown in FIG. 2, undrawn nylon 6,6 monofil is fed to a inch diameter snubbing pin maintained at a temperature of 175 C., passing thereabout two turns. The yarn is pulled from the pin at a draw roll speed of 1,980 feet per minute for a draw ratio of 4.22, the resulting monofil being denier. The yarn in passing to the draw roll contacts the surface of flange 42 which is 5 inches in diameter. The rotational speed of the flange is such that about 30 turns per inch of false twist are inserted. The distance from pin to flange is 13.5 inches so that the yarn is appreciably cooled, and is thus heat set, while in twisted condition for about 22.7 milliseconds. The finish formulation applied is as follows:

80 percent mineral oil stoke viscosity at C.)

10 percent condensate of 3 mols of ethylene oxide with a mixture of straight chain fatty alcohols having an average size chain length of 13 carbon atoms 10 percent dimethyl amide of pelargonic acid, and is applied to give about a 1 percent pickup based on the weight of the yarn. The resulting yarn has a torque of 36.5 seconds, an ESST of 50, a boardability factor of 1.17, a twist liveliness of 527 and processes without problems on a circular hosiery knitting machine.

Hoselegs knit therefrom in plain stitch constructions are characterized by improved ankle conformity and freedom from fabric distortion encountered using different draw-false twist conditions with the same apparatus.

EXAMPLE II Example I is repeated except that the finish formulation is as follows:

70 percent butyl stearate 10 percent condensate of 3 mols ethylene oxide and 1 mol tridecyl alcohol 20 percent diethanolamide of a straight chain fatty acid cut of cocoa having an average chain length of 14 carbon atoms. Again minimal problems result during the knitting opera tion.

EXAMPLE 111 Example I is repeated with the exception thatthe yarn travels directly from the draw roll to the baloon guide without passing through the finish applicator. The yarn has about identical torque, ESST, boardability factor and twist-liveliness values as the yarn of Example I but the yarn cannot be economically processed on conventional hosiery circular knitting machines because of excessive breaks.

EXAMPLE IV Example 111 is repeated. As the yarn travels from the pirn to the first guide of the knitting machine, the finish of Example I is applied thereto to give a 1 percent pickup. The yarn processes only marginally better than in Example 111 because of tension fluctuation and tension increase between the pirn and guide.

The yarn of the invention has a tenacity (grams/denier) of about 3 to 7, preferably 4 to 6 and an elongation at the break of about 15 to 50 percent, preferably 25 to percent.

The yarn is preferably collected on the pirn by means of a ring and traveller inserting a low degree of real twist, it to 1 turn per inch in the opposite direction of the false twist in the yarn. This facilitates takeoff of the yarn from the pirn during the knitting operation. If the yarn is wound onto the pirn with a low degree of twist insertion in the same direction as the previously inserted false twist, the yarn s springs off the package presenting control problems during the knitting operation.

It will be appreciated that the instant specification and examples are set forth by way of illustration and not limitation, and that various modifications and changes may be made without departure from the spirit and scope of the present invention.

What is claimed is:

1. False twist textured nylon continuous monofilament yam having a boardability factor less than about 2.0, a twist liveliness of less than about 600 and having uniformly applied thereon about 0.5 to 2.0 percent by weight based on the weight of the yarn a finish consisting essentially of 40 to percent of a lubricant selected from the class consisting of mineral oil having a viscosity of about 8 to 25 centistokes at 25 C., an ester of a carboxylic acid having a chain length of about 12 to 18 carbon atoms with an alkyl alcohol having a chain length of about three to seven carbon atoms and mixtures thereof; 5 to 35 percent of a nonionic alkoxylated emulsifier and 5 to 30 percent of a lower alkanolamide of a fatty carboxylic acid having a chain length of about eight to 18 carbon atoms as an antistatic agent.

2. The yarn of claim 1 having a boardability factor of about 1.0 to 2.0, a twist liveliness of about 450 to 600 and wherein the lubricant is mineral oil or an ester of a straight chain fatty acid with an aliphatic monohydric alcohol, the emulsifier is the condensate of ethylene oxide with an organic compound containing an active hydrogen atom and the antistatic agent is a monoor dilower alkanol amide of a straight chain fatty acid.

3. The yarn of claim 2 having thereon about 0.75 to 1.25 percent of the finish.

4. The yarn of claim 2 having thereon about 1.0 percent of the finish.

5. The yarn of claim 2 comprising nylon 6,6.

6. A knit structure comprising the yarn of claim 5.

7. The yarn of claim 2 comprising nylon 6.

8. A knit structure comprising the yarn of claim 7.

9. A knit article comprising the yarn of claim 20.

10. The yarn of claim 2 wherein the emulsifier is the condensate of about 2 to 12 mols of ethylene oxide per mol of fatty acid or alcohol having a chain length of about eight to 20 carbon atoms.

11. The yarn of claim 2 wherein the antistatic agent is the monoor dimethanol and/or ethanol amide of a mixture of fatty acids derived for cocoa.

12. A process for producing a nylon monofilament yarn suitable for knit goods which comprises heating said yarn by passing said yarn at about 1,000 to 5,000 feet per minute through a 2 to 30 inch heating zone maintained at about to 220 C., friction false twist texturing said yarn under conditions to impart about 20 to 40 turns per inch of false twist to said yarn, said twist running back to said heating zone, cooling the yarn for about 5 to 50 milliseconds between said heating means and said false twist insertion means, uniformly applying on yarn about 0.5 to 2.0 percent by weight based on the weight of the yarn a finish consisting essentially of 40 to 90 percent of a lubricant selected from the class consisting of mineral oil having a viscosity of about 8 to 25 centistokes at 25 C., an ester of a carboxylic acid having a chain length of about 12 to 18 carbon atoms with an alkyl alcohol having a chain length of about three to seven carbon atoms and mixtures thereof; 2 to 35 percent of a nonionic alkoxylated emulsifier and 5 to 30 percent of a lower alkanolamide of fatty carboxylic acid having a chain length of about eight to 18 carbon atoms as an antistatic agent, and then taking-up said yarn using a ring and traveller mechanism while inserting low real twist into said yarn in the opposite direction of said false twist.

PO-W5O UNITED STATES PATENT OFFICE 9 CERTIFICATE OF CORRECTION- Pacent N 3.651.633 I Dated March l8, m2

I Inventofls) William George Steinmiller It is certified that error appears in the above-identified patent and that: said Letters Patent are hereby corrected as shown below:

Column 2,line 50, "described" should be disclosed Column 3, under heading "Number of Links", "17 17 408" Column 3, under heading "Number of Courses", first line, "408" was omitted.

Column 5, line 66, after the word "percent" and priorto "conventionally", insert for Column 8, line 74, "ration" should be ratio Cl i 11, line 3, "for" should be from Claim 9, 20" should be 2 Signed and sealed this 1st day of August 1972.

(SEAL) Attest:

ED IARD M,FLETCHER,JR. ROBERT GOTTSCHALK Attestlng Officer Commissioner of Patents 

1. False twist textured nylon continuous monofilament yarn having a boardability factor less than about 2.0, a twist liveliness of less than about 600 and having uniformly applied thereon about 0.5 to 2.0 percent by weight based on the weight of the yarn a finish consisting essentially of 40 to 90 percent of a lubricant selected from the class consisting of mineral oil having a viscosity of about 8 to 25 centistokes at 25* C., an ester of a carboxylic acid having a chain length of about 12 to 18 carbon atoms with an alkyl alcohol having a chain length of about three to seven carbon atoms and mixtures thereof; 5 to 35 percent of a nonionic alkoxylated emulsifier and 5 to 30 percent of a lower alkanolamide of a fatty carboxylic acid having a chain length of about eight to 18 carbon atoms as an antistatic agent.
 2. The yarn of claim 1 having a boardability factor of about 1.0 to 2.0, a twist liveliness of about 450 to 600 and wherein the lubricant is mineral oil or an ester of a straight chain fatty acid with an aliphatic monohydric alcohol, the emulsifier is the condensate of ethylene oxide with an organic compound containing an active hydrogen atom and the antistatic agent is a mono- or di- lower alkanol amide of a straight chain fatty acid.
 3. The yarn of claim 2 having thereon about 0.75 to 1.25 percent of the finish.
 4. The yarn of claim 2 having thereon about 1.0 percent of the finish.
 5. The yarn of claim 2 comprising nylon 6,6.
 6. A knit structure comprising the yarn of claim
 5. 7. The yarn of claim 2 comprising nylon
 6. 8. A knit structure comprising the yarn of claim
 7. 9. A knit article comprising the yarn of claim
 2. 10. The yarn of claim 2 wherein the emulsifier is the condensate of about 2 to 12 mols of ethylene oxide per mol of fatty acid or alcohol having a chain length of about eight to 20 carbon atoms.
 11. The yarn of claim 2 wherein the antistatic agent is the mono- or di- methanol and/or ethanol amide of a mixture of fatty acids derived from cocoa.
 12. A process for producing a nylon monofilament yarn suitable for knit goods which comprises heating said yarn by passing said yarn at about 1,000 to 5,000 feet per minute through a 2 to 30 inch heating zone maintained at about 150* to 220* C., friction false twist texturing said yarn under conditions to impart about 20 to 40 turns per inch of false twist to said yarn, said twist running back to said heating zone, cooling the yarn for about 5 to 50 milliseconds between said heating means and said false twist insertion means, uniformly applying on yarn about 0.5 to 2.0 percent by weight based on the weight of the yarn a finish consisting essentially of 40 to 90 percent of a lubricant selected from the class consisting of mineral oil having a viscosity of about 8 to 25 centistokes at 25* C., an ester of a carboxylic acid having a chain length of about 12 to 18 carbon atoms with an alkyl alcohol having a chain length of about three to seven carbon atoms and mixtures thereof; 2 to 35 percent of a nonionic alkoxylated emulsifier and 5 to 30 percent of a lower alkanolamide of fatty carboxylic acid having a chain length of about eight to 18 carbon atoms as an antistatic agent, and then taking-up said yarn using a ring and traveller mechanism while inserting low real twist into said yarn in the opposite direction of said false twist.
 13. The process of claim 12 wherein said yarn comprises nylon
 6. 14. The process of claim 12 wherein said yarn comprises nylon 6,
 6. 